1. Field of the Invention
The present invention relates to a track roller bearing with stud for smoothly guiding linear motion and so forth in a machine tool or industrial robot and so forth, which is also commonly used as a cam follower.
2. Description of the Prior Art
FIG. 1 is an example of a track roller bearing with stud of the prior art.
As shown in FIG. 1, this track roller bearing with stud is equipped with stud 1, outer ring 2, side plate 3, a plurality of rollers 4 and cage 6.
Stud 1 is composed in the shape of a shaft in which is formed, in order from one end surface, flange 1a, a track portion in the form of track surface 1b, side plate engaging portion 1c, attaching portion 1d and threaded portion 1e.
Outer ring 2 is in the form of a thick-walled ring in which one end is prevented from coming out in the axial direction by flange 1a and having a larger diameter than the outer diameter of the flange 1a. Track surface 2b is formed on the inside of outer ring 2. Outer ring 2 is installed while being allowing to rotate freely with respect to track surface 1b of stud 1.
A plurality of rollers 4 are juxtaposed in the form of rolling elements between track surfaces 1b and 2b.
In addition, cage 6 is provided which retains a plurality of rollers 4 between track surfaces 1b and 2b at mutual intervals.
Side plate 3 is located on the other end of outer ring 2 corresponding to flange 1a and is composed of a doughnut-shaped plate having a diameter similar to the outer diameter of the flange 1a. The inner diameter portion fits into side plate engaging portion 1c of stud 1 and prevents outer ring 2, the plurality of rollers 4 and cage 6 from coming out in the axial direction in cooperation with flange 1a.
In a track roller bearing with stud composed in this manner, outer ring 2 normally rotates relative to stud 1.
Stud 1 has lubricant supply hole 1g extending roughly over its entire length in its axial center. Lubricating holes 1h and 1i, which are respectively connected to track surface 1b and attachment portion 1d, are opened in the supply hole 1g. These supply hole 1g, lubricating holes 1h and 1i form a lubricating path for lubricant. Lubricant supply ports 1m and 1n are formed in both ends of stud 1. These lubricant supply ports 1m and 1n serve as lubricating oil intake ports for lubricant that passes through the lubricating path.
In addition, as shown in FIG. 2, slotted screwdriver groove 1p is formed in the end surface on the side of flange 1a of stud 1.
FIG. 3 shows an example of typical usage of a track roller bearing with stud.
As shown in FIG. 3, stud 1 of the track roller bearing with stud is inserted into housing 8 of a frame equipped on a machine tool and so forth, nut 11 is screwed onto threaded portion 1e of stud 1 protruding from the opposite side of the frame juxtaposed about spring washer 10, and stud 1 is tightened to fix in position by either turning this nut 11 with a wrench and so forth or by engaging a screwdriver into slotted screwdriver groove 1p and turning stud 1.
Normally, the surface of the outer diameter of outer ring 2 makes sliding contact with the track of a linear path or the track of a cam mechanism in the form of track 13 which causes outer ring 2 to rotate resulting in relative motion with the track 13.
In the attached state described above, in the case of lubricating with grease, a grease supply device in the form of a grease nipple (not shown) is attached to either of lubricant supply ports 1m or 1n, whichever makes lubrication work easier. The lubricant supply port that is not used is blocked with a plug (not shown). In addition, lubricating hole 1i, which opens into attaching portion 1d of stud 1, is blocked by housing 8. A suitable amount of grease is supplied by a grease gun and so forth into the above grease nipple which causes grease in the form of lubricant to fill the inside of the above lubricating path. This results in grease being supplied to track surfaces 1b and 2b of stud 1 and outer ring 2 as well as rollers 4 from lubricating hole 1h.
FIGS. 4 and 5 show a track roller bearing with stud as another example of the prior art.
This track roller bearing with stud is composed in the same manner as the above track roller bearing with stud with the exception of the points described below, and the same reference numerals are used for those constituent members that are identical or corresponding to the track roller bearing with stud described above.
Hexagonal hole 1r is formed in the end surface of stud 1 on the flange side of this track roller bearing with stud instead of the slotted screwdriver groove 1p. When attaching or removing, a hexagonal wrench is inserted into this hexagonal hole 1r to turn stud 1. This hexagonal hole 1r allows tightening to be performed more reliably than slotted screwdriver groove 1p, thereby offering the advantage of a more secure installation.
In addition, in terms of processing as well, although having a slotted screwdriver groove had to be processed by cutting to form grooves for a process of milling cutter and so on, since having hexagonal hole 1r offers the advantages of hexagonal hole 1r being able to be formed simultaneous to forging when obtaining the parent form of stud 1, thereby reducing the number of processing steps, and not having the processing difficulty associated with the ordinary screwdriver groove 1p, it has come to be widely used in recent years.
However, in the track roller bearing with stud having hexagonal hole 1r, lubricant supply port 1n is only provided on the end surface of stud 1 on the side of threaded portion 1e, to which grease nipple 15 is attached.
At present, track roller bearings with studs are widely used in various technical fields, and there is an extremely high demand for them. There is therefore a need for a track roller bearing with stud having a hexagonal hole that offers even easier handling.
The track roller bearing with stud having hexagonal hole (1r) that has come into wide use in recent years has the problem of the lubricant supply port to which grease nipple 15 can be attached only being provided on the side opposite from the hexagonal hole 1r, thus making it necessary to only provide lubrication from one side.